Microsoft founder Bill Gates cheers on American table-tennis star Ariel Hsing during her match against Li Xiaoxia of China at the London Olympics last Sunday. Gates and Warren Buffett have played a few practice shots with Hsing while she attended Berkshire Hathaway's annual meeting to give practice lessons. Hsing calls the two "Uncle Warren and Uncle Bill."AP

The time-honored American institution of a company-financed pension is going the way of the company car.

The defined-benefit pension is a vestige of a bygone era, says Alex Pollock, a scholar at the American Enterprise Institute, who also questions the idea of Uncle Sam guaranteeing pensions. That is a system that started back in the 1970s at the suggestion of Nat Weinberg, an economist for the United Auto Workers union.

In 1988, about two-thirds of companies offered pensions, according to government records. But by 2010, that number was down to less than one-third.

And the large majority of companies remaining have underfunded their pensions, knowing that if anything goes wrong, the government will often bail them out through its Pension Benefit Guaranty Corp. (PBGC), according to Pollock.

In fact, 80 percent of the 27,000 single-company pension plans insured by the PBGC are considered woefully underfunded, meaning their liabilities exceed the funds assets.

As an example, PBGC Director Joshua Gotbaum points to American Airlines. Since it filed for bankruptcy, it has indicated it wants to jettison its pensions.

If the idea is OK’d, Gotbaum says, it would increase PBGC’s liability by $9 billion.

And that’s not something the PBGC can easily absorb.

The PBGC is funded by a combination of insurance premiums, investment income and other means, not by taxpayers. But its growing deficit — $26 billion and rising — has critics worried that it will need a taxpayer bailout.

“If PBGC’s finances aren’t reformed, the agency will eventually run out of money to pay benefits,” PBGC Director Joshua Gotbaum told the House panel on Health, Employment, Labor and Pensions recently.

Gotbaum, in his testimony, said, “We cannot ignore our own financial condition any more than we would of the pension plans we insure.” The PBGC backstops the pensions of some 44 million participants in some 27,000 defined-benefit single-employer and multi-employer plans. The maximum benefit for a participant in a failed plan is about $57,000 a year.

A PBGC spokesman emphasized to The Post that the agency “in its history has never taken taxpayer money, and there is no immediate expectation of [needing] taxpayer money.” He also noted that the agency has just raised premiums. He said the agency throughout its history has “usually had deficits.”

The PBGC’s problems reflect just how many private-sector employers have bailed out on pensions in a short period of time. As recently as 1999, the agency had a $7 billion surplus.